As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) INITIALLY AFTER PAX DOOR CLOSED. THE ASU (AIR START UNIT) AND BOTH PACKS WERE PUT ON, `SMOKE AFT LAV` (W) MSG WAS LIT, AND OFFENSIVE ODOR REPORTED BY FA. (SMELL LIKE PLASTIC). ANOTHER ASU CONNECTED AND PERFORMED SMOKE DETECTOR TEST AND A/C WAS RTS, AFTER TAKING OFF THE `SMOKE AFT LAV` (W) MSG WAS RE-LIGHTED AROUND 3,500 FT. CORRECTIVE ACTION: R/R LAVATORY SMOKE DETECTOR (TC# 20190521004)